// http://lists.dragonflybsd.org/pipermail/users/2019-September/358280.html
const _dragonflyABIChangeVersion = 500705

func supportsABI(ver uint32) bool {
	osreldateOnce.Do(func() { osreldate, _ = SysctlUint32("kern.osreldate") })
	return osreldate >= ver
}

type SockaddrDatalink struct {
	Len    uint8
	Family uint8
	Index  uint16
	Type   uint8
	Nlen   uint8
	Alen   uint8
	Slen   uint8

// http://lists.dragonflybsd.org/pipermail/users/2019-September/358280.html
const _dragonflyABIChangeVersion = 500705

func supportsABI(ver uint32) bool {
	osreldateOnce.Do(func() { osreldate, _ = SysctlUint32("kern.osreldate") })
	return osreldate >= ver
}

// SockaddrDatalink implements the Sockaddr interface for AF_LINK type sockets.
type SockaddrDatalink struct {
	Len    uint8
	Family uint8
	Index  uint16

		return "", err
	}

	// Throw away terminating NUL.
	if n > 0 && buf[n-1] == '\x00' {
		n--
	}
	return string(buf[0:n]), nil
}

func SysctlUint32(name string) (value uint32, err error) {
	// Translate name to mib number.
	mib, err := nametomib(name)
	if err != nil {
		return 0, err
	}

	// Read into buffer of that size.
	n := uintptr(4)

var (
	osreldateOnce sync.Once
	osreldate     uint32
)

func supportsABI(ver uint32) bool {
	osreldateOnce.Do(func() { osreldate, _ = SysctlUint32("kern.osreldate") })
	return osreldate >= ver
}

// SockaddrDatalink implements the Sockaddr interface for AF_LINK type sockets.
type SockaddrDatalink struct {
	Len    uint8
	Family uint8
	Index  uint16

	if err != nil {
		return "", err
	}
	n := len(buf)

	// Throw away terminating NUL.
	if n > 0 && buf[n-1] == '\x00' {
		n--
	}
	return string(buf[0:n]), nil
}

func SysctlUint32(name string) (uint32, error) {
	return SysctlUint32Args(name)
}

func SysctlUint32Args(name string, args ...int) (uint32, error) {
	mib, err := sysctlmib(name, args...)
	if err != nil {
		return 0, err

		{"Syscall12", Func, 0},
		{"Syscall15", Func, 0},
		{"Syscall18", Func, 12},
		{"Syscall6", Func, 0},
		{"Syscall9", Func, 0},
		{"SyscallN", Func, 18},
		{"Sysctl", Func, 0},
		{"SysctlUint32", Func, 0},
		{"Sysctlnode", Type, 2},
		{"Sysctlnode.Flags", Field, 2},
		{"Sysctlnode.Name", Field, 2},
		{"Sysctlnode.Num", Field, 2},
		{"Sysctlnode.Un", Field, 2},
		{"Sysctlnode.Ver", Field, 2},